The exchange occurred at the end of a discussion about former DNC chair Donna Brazile’s conclusion that the Clinton campaign had control over the DNC and that the “system” was rigged “to throw the primary to Hillary.”

“This is a real problem,” Warren said. “But what we’ve got to do as Democrats now, is we’ve got to hold this party accountable.”

Warren said the moment is a test of DNC Chair Tom Perez’s leadership.

“And either he’s going to succeed by bringing Bernie Sanders and Bernie Sanders representatives into this process and they’re going to say, ‘It’s fair, it works, we all believe it.’

Or, he’s going to fail, and I very much hope he succeeds,” Warren said. “I hope for Democrats everywhere, I hope for Bernie and for all of Bernie’s supporters that he’s going to succeed.”

Warren speaks to a crown gathered at Logan Airport in Boston on Jan. 28, 2017, the day after President Trump signed an executive order on his travel ban. Nicolaus Czarnecki, AP